"Imagine if cavemen had been shown the smartphone you’re using to record me. What would they have thought about this special rock? Now imagine that Oumuamua is the iPhone, and we are the cavemen"–Harvard astronomer Avi Loeb is worth hearing out https://t.co/hKJoL5mYu8

It’s not the space rock, it’s the stories we tell each other about the space rock. As someone who’s been both an avid sf reader and a Cynic for pushing 60 years now, I found Professor Loeb’s whole argument charming:

“I don’t care what people say,” asserts Avi Loeb, chairman of Harvard University’s astronomy department and author of one of the most controversial articles in the realm of science last year (and also one of the most popular in the general media). “It doesn’t matter to me,” he continues. “I say what I think, and if the broad public takes an interest in what I say, that’s a welcome result as far as I’m concerned, but an indirect result. Science isn’t like politics: It is not based on popularity polls.”

Prof. Abraham Loeb, 56, was born in Beit Hanan, a moshav in central Israel, and studied physics at the Hebrew University of Jerusalem as part of the Israel Defense Forces’ Talpiot program for recruits who demonstrate outstanding academic ability. Freeman Dyson, the theoretical physicist, and the late astrophysicist John Bahcall admitted Loeb to the Institute for Advanced Study in Princeton, whose past faculty members included Albert Einstein and J. Robert Oppenheimer. In 2012, Time magazine named Loeb one of the 25 most influential people in the field of space. He has won prizes, written books and published 700 articles in the world’s leading scientific journals. Last October, Loeb and his postdoctoral student Shmuel Bialy, also an Israeli, published an article in the scientific outlet “The Astrophysical Journal Letters,” which seriously raised the possibility that an intelligent species of aliens had sent a spaceship to Earth.

The “spaceship” in question is called Oumuamua. For those who don’t keep up with space news, Oumuamua is the first object in history to pass through the solar system and be identified as definitely originating outside of it. The first interstellar guest came to us from the direction of Vega, the brightest star in the Lyra constellation, which is 26 light-years from us. In the 1997 film “Contact,” it’s the star from which the radio signal is sent to Jodie Foster.

Oumuamua was actually discovered by a Canadian astronomer, Robert Weryk, using the Pan-STARRS telescope at the Haleakala Observatory in Hawaii. “Oumuamua” is Hawaiian for “first distant messenger” – in a word, “scout.” It was discovered on October 19, 2017, suspiciously close to Earth (relatively speaking, of course: Oumuamua was 33 million kilometers away from us when it was sighted – 85 times farther than the moon is from Earth)…What does it feel like to sit next to colleagues in a university lunchroom a day after publishing an article arguing that Oumuamua may actually be a reconnaissance spaceship?

Loeb: “The article I published was written, in part, on the basis of conversations I had with colleagues whom I respect scientifically. Scientists of senior status said themselves that this object was peculiar but were apprehensive about making their thoughts public. I don’t understand that. After all, academic tenure is intended to give scientists the freedom to take risks without having to worry about their jobs. Unfortunately, most scientists achieve tenure – and go on tending to their image. As children we ask ourselves about the world, we allow ourselves to err. Ego doesn’t play a part. We learn about the world with innocence and honesty. As a scientist, you’re supposed to enjoy the privilege of being able to continue your childhood. Not to worry about the ego, but about uncovering the truth. Especially after you get tenure.”

Without tenure you wouldn’t have published the article?

“I suppose not. It’s not just the tenure. I’m head of the astronomy department, and founding director of the Black Hole Initiative [an interdisciplinary center at Harvard dedicated to the study of black holes]. In addition, I’m director of the Board on Physics and Astronomy of the National Academies. So it could be that I’m committing image suicide, if this turns out to be incorrect. On the other hand, if it turns out to be correct, it’s one of the greatest discoveries in human history. For us to make progress in understanding the universe, we need to be credible, and the only way to be credible is to follow what you see, not yourself. Besides, what’s the worst thing that can happen to me? I’ll be relieved of my administrative duties? This will bring the benefit that I’ll have more time for science.”…

Was ‘Oumuamua a spaceship? Almost certainly not! Are we, this generation, the readers of this blog, ever likely to know whether ‘Oumuamua was a spaceship? Again — signs point to ‘No’. But the theory is enough, perhaps, to change how (if, when) we spot the next extrastellar object.

Tom Scocca puts it nicely (in the original sense of that word):

… No one will ever track down ‘Oumuamua to settle the question, but the purpose of Loeb’s argument was to be unsettling—to demonstrate that being the chair of Harvard’s astronomy department no longer means rejecting the possibility of alien technology, that when ‘Oumuamua departed, it carried away with it a whole set of presumptions that had been operating under the guise of conclusions…

The more we know, the more we know we don’t know. ‘Oumuamua entered our solar system from a direction nothing else had entered it from, at a speed nothing else had arrived at, with a shape nothing else had ever had. It accelerated, by some means no one had ever previously observed, and went away. Whether it came from a technosphere built by aliens was almost beside the point, or too narrow a question: what is certain is that there is at least one thing of its kind in the universe, which is infinitely more things of that kind that we knew existed in the universe two years ago.

Who knows? Perhaps ‘Oumuamua is the extrastellar equivalent of a mousetrap set by careful householders around the perimeter of an as-yet-mouseless home. Have we triggered that trap? If so, are the original trap-setters even around to care? It’s the speculation that’s the fun part!

oumuamua came to the solar system looking for intelligent life and that’s why it left so fast

‘Oumuamua entered the solar system at a speed of 26 km/s. At that speed it would take 50,000 years to get here from the nearest star. I don’t think that’s a credible speed for a starship or even an interstellar probe. If you’re doing it at all you would want to do it in less time.
If it’s artificial it’s probably a discarded rocket stage or fuel tank, maybe from something slowing down from much higher speeds as it entered the system.

Snow’s raining down. A bit weird because it’s 0 but the snow is wet, so it’s a whole lot warmer somewhere above. But it’s also a fine snow. Cold and thin, but wet. They say sleet in the afternoon and then freezing rain, all the while bitter cold. There’s some soft booms going on too. The cats and dog are pleased with themselves for arranging this magnificent warm hollow with food supply and radiators.

@raven: I saw Black Robe, unforgettable after all this time. Incredible scenes of canoes in northern lake wilderness. For years after that we used to say “Black robe, black robe” to each other in the voice of the small Algonquin mystic.

The more we know, the more we know we don’t know. ‘Oumuamua entered our solar system from a direction nothing else had entered it from, at a speed nothing else had arrived at, with a shape nothing else had ever had. It accelerated, by some means no one had ever previously observed, and went away.

At times I wonder which is more blinding: Our ignorance? Or our hubris?

It was discovered on October 19, 2017, suspiciously close to Earth (relatively speaking, of course: Oumuamua was 33 million kilometers away from us when it was sighted – 85 times farther than the moon is from Earth)…

Suspiciously…. BWAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA….. Lots of objects come within 33 million miles of earth, happens all the time.

“Oh, but this is the first one from interstellar space.”

Bullshit. It’s the first one we know of. And remember, we did not see it until it was that close. The solar system is a big place. It is very likely that there is a planet** as much 10 times the mass of the Earth out beyond the Kuiper belt, marshaling the exotic orbits of several trans Neptunian objects and planetismals, and our ever seeing it will have as much to do with luck as it will with technology and skill. Dozens of interstellar travelers as small and dark as Oumuamua could be passing thru our solar system every year and we’d never know it. This one just happened to pass by close enough at a time when our technology finally was capable of observing it.

The first interstellar guest came to us from the direction of Vega, the brightest star in the Lyra constellation, which is 26 light-years from us. In the 1997 film “Contact,” it’s the star from which the radio signal is sent to Jodie Foster.

This is the kind of journalistic malpractice one finds in supermarket tabloids. They’ve calculated Oumuamua’s trajectory back to see if they could figure out where it came from. Guess what? As far as they can tell, it doesn’t come from anywhere. Which just really means they can’t trace it to any observable star, either because the star it comes from is so distant we can’t see it, hidden in a cloud of gas and dust, or that it’s path has been altered by passing close by another object.

None of this is to denigrate Avi Loeb. He is a well respected and very accomplished astrophysicist. But having postulated this exceedingly unlikely theory for Oumuamua’s existence, the burden of proof lies squarely on his shoulder’s. He needs to have more than just conjecture and unanswerable questions to back up his theory. As of right now, Occams razor says it’s just a piece of rock, possibly part of a planet that was blown up in a supernova billions of years ago.

**The case for the existence of Planet 9 keeps getting stronger as they find more and more objects in orbits predicted by Batygin and Brown. But having a projected orbit that goes from 1200 AU at aphelion to 200 AU at perihelion and lasting anywhere from 10,000-20,000 years, it could be hundreds of generations before it is close enough for any human on Earth to see it.

A cryoseism, also known as an ice quake or a frost quake,[1][2][3][4] is a seismic event that may be caused by a sudden cracking action in frozen soil or rock saturated with water or ice.[5] As water drains into the ground, it may eventually freeze and expand under colder temperatures, putting stress on its surroundings. This stress builds up until relieved explosively in the form of a cryoseism.[1][6]

The first time I heard them it kind of freaked me out. Could not figure out what they were.

Here we report the detection, at 30σ significance, of non-gravitational acceleration in the motion of ‘Oumuamua. […] we find comet-like outgassing to be a physically viable explanation, provided that ‘Oumuamua has thermal properties similar to comets.

Not my Occam’s razor, but the hundreds of other astrophysicists and planetologists and cosmologists who have written up papers about Oumuamua. I have merely read a dozen or so articles summarizing their papers.

Avi Loeb is spitballing. I suspect he is even having a little fun with it. There is nothing wrong with that. But extraordinary claims require extraordinary evidence.

South Central Indiana was blanketed with about four inches of snow starting after dark last night. We watched the first couple of hours cover the deck, about two inches in two hours, fast, wind whipped, large flakes. It was beautiful. The cats this morning are grump, I open the door to show them what happened, they glare balefully, snarl at each other, and are refusing to eat breakfast. Did I mention they are indoor / outdoor cats? I think they expect me to clean that mess up.

@Raven: I was reading an article a couple weeks ago about Fast Radio Bursts and the discovery of only the 2nd FRB repeater ever observed. The theory of alien communication as an explanation for this phenomena was briefly touched on and somebody gave a very good explanation for why we humans see aliens whenever we find something we can’t explain.

It’s hard wired into us, part of our “flight or fight” reflex. All the way back when we were just another item on the menu, assuming that rustle in the bushes was a lion sneaking up to eat us and not just the wind gave us a leg up the tree ahead of him. If it wasn’t a lion, “Well hey, look at this fruit I found.”

I don’t think you are disagreeing with Loeb. You emphasize how little we know. So does he. Given how little we know, a lot of possibilities are compatible with our evidence.

If Loeb was claiming that he could rule out its being a random piece of rock, he’d need better evidence than he has. But that’s not what he said. He raised a possibility, i.e. pointed out something else compatible with our evidence.

And the less evidence we have, the more possibilities there are compatible with it.

There’s no hubris in saying that — quite the opposite, to say that is to admit how little we know.

All of us think the alien scout possiblity is a low-odds one. So does Loeb. In my own opinion, the odds that it’s an alien scout are astronomically low. But I don’t think there is anything wrong with an expert’s speculating about low-odds possibilities.

They’re not here for us, they’re here to guide the evolution of the methane-based life forms on Titan. (A probe found that some unexplained process on Titan’s surface appears to be consuming acetylene and producing methane IIRC).

Too hard to locate and post a link on phone. I really want both of these stories to have extraterrestrial-life explanations. I’ve read sci-fi my whole life dang it, and I’m running out of time to meet the aliens.

The hubris or ignorance I am referring to is not Loeb’s, it’s not even Scocca who is just quoting whoever said,

The more we know, the more we know we don’t know. ‘Oumuamua entered our solar system from a direction nothing else had entered it from, at a speed nothing else had arrived at, with a shape nothing else had ever had. It accelerated, by some means no one had ever previously observed, and went away.

To which I said, “Bullshit. It’s the first one we know of.”

I am speaking to the fact that just because nobody has ever seen a thing before, doesn’t mean it never happened before.

Back in the 1950s, John W. Campbell, the editor of Astounding Science Fiction Magazine, ran an editorial describing the problems scientists from 1939 would have had trying to make sense of a guided anti-aircraft missile from 1950. I forget the missile’s name, but it was a radio-guided ram-jet. I forget many of the details, but, for example, they would have been unable to figure out what the radio was. They could tell it was lumps of incredibly pure germanium configured as if they were some kind of electrical device, but they could not have detected the impurities in the germanium that turned them into transistors. They could have seen how fuel was pumped into the hollow tube, but they would not have been able to figure out how it did anything but burn, because the ram-jet had to be travelling close to the speed of sound to start delivering thrust. It seems very likely that if we encountered an actual mechanism from an advanced civilization we’d have similar problems. We might be able to determine it was a manufactured object, but we probably couldn’t tell how it worked and we might not even be able to tell that it was manufactured.

(A probe found that some unexplained process on Titan’s surface appears to be consuming acetylene and producing methane IIRC).

The last I read was that there are several explanations for the methane, only one of which involves life.

Enceladus is known to have liquid water and Europa is suspected to as well (trying to remember if that is now a certainty, my google fu doesn’t help) Both are possible locations for extraterrestrial life.

@Baud: Shape? I think it’s spin is even neater: It’s end over end. Which seems to be the least likely for a space ship (from a human point of view, maybe aliens would find that more natural? more comfortable?)

@Raven: Yeah, and I only know what I read, which as much as it is, is infinitesimal compared to what these guys read every year, and to be honest very shallow too. I rarely get into the math of this stuff and when I do it is only to the extent that I get as good a picture as I need to to understand what they are saying. Most times I just skip over that part.

@oldster: Well, except that your argument works equally well as an argument that [eta: we should take seriously that] there are a God or Gods. Or, heck, that there are pink flying elephants in a cave under the Swiss Alps with special radar/seismic-wave-spoofing technology to avoid detection. @OzarkHillbilly is absolutely right to say

extraordinary claims require extraordinary evidence.

and I’ll note that this is part of the scientific method, of scientific culture. That sentence can be found in debunkings of ESP and many other sorts of woo.

@oldster: @OzarkHillbilly: The *only* part that makes me sit up and take notice is the possibility that ‘Oumuamua’s acceleration might be unexplainable. But from that papar I linked-to, that doesn’t seem likely. If it DID turn out that the acceleration was unexplainable, hey presto, I think it would be reasonable to ask whether ‘Oumuamua was …. not natural, but artificial.

I knew Carl Sagan (name drop, but necessary). He would not be happy to see that a phrase he created to question irrational, faith-based belief models is now routinely misused to set higher bars for some kinds of scientific speculation than for others. There is only one scientific method, and equally there is only one standard of evidence within it. David Demings says it better here: https://link.springer.com/article/10.1007/s11406-016-9779-7.

The last thing Native Americans need is to host a bunch of racist white kids on a missions trip. There are plenty of ways to unlearn white supremacy without further endangering people of color. We are not your (or your children's) object lesson. https://t.co/DOqB88q9N4

@Chetan Murthy: It is a question but it being merely unexplainable would not be enough to sway my opinion. We can’t even begin to explain dark matter or dark energy and in fact only know of their existence** by their observed influence upon the cosmos.

**is dark matter actually matter? or some property of gravity we are wholly ignorant of? what is dark energy? what could possibly cause the expansion of the universe to accelerate?

The origin of ECREE lies in eighteenth-century Enlightenment criticisms of miracles. The most important of these was Hume’s essay On Miracles. Hume precisely defined an extraordinary claim as one that is directly contradicted by a massive amount of existing evidence. For a claim to qualify as extraordinary there must exist overwhelming empirical data of the exact antithesis.

The claim here is that ‘Oumuamua might be an alien scout. There are *two* data-points that are adduced: (1) hyperbolic trajectory, and (2) acceleration on the way out of the solar system. The first is easily explained by “first interstellar object” (no need to posit artificial) and the second, from what I can see, admits of a natural explanation. This gives us a simple explanation, in line with our current understanding of the universe. Which is: “There’s no evidence that there are aliens; none whatsoever.”

What evidence is there that this object is artificial? Well, if the acceleration had no natural explanation, that’d work. But otherwise? What?

So yeah, this *is* an extraordinary claim, b/c it *is* directly contradicted by a massive body of evidence — evidence that tells us there are no aliens.[1] As I wrote above, I don’t believe in pink flying elephants, either.

[1] yes yes yes, I also know about the Drake Equation. And yes yes yes I also want to believe in aliens. But that’s not the same as *evidence*.

@Procopius: Didn’t something similar happen during the Renaissance when Roman architectural drawings were found and people couldn’t work out what the gaps under the floors and in the walls were for? I read somewhere that it was only when the principles of central heating were re-discovered several hundreds of years later that they understood.

It is a question but it being merely unexplainable would not be enough to sway my opinion.

Well, this is a fact-set where things should be governed by General Relativity and it’s approximation in Newtonian gravitation, right? So if in fact the object’s trajectory didn’t fit that [along with other natural factors, like cometary outgassing], we’d have to say that either GenRel is wrong, or the object is powered somehow, right?

The thing about dark {matter,energy} is that they’re theorized to account for behaviour [at a much, much bigger scale] that does not comport with GenRel, right? And nobody knows what they are or how they work, but they -do- know that in order for the equations to work out, there’s gotta be something there. More precisely, there’s not *nothing* there. And similarly, I’d say that if it turned out that ‘Oumuamua’s trajectory was unexplainable, we might not be able to say why, but “unexplainable” would rule out “natural objects”.

There’s a funny little apostrophe at the start of the object’s name, that might make you think it is beginning a quotation. From Wiki: “The first character is a Hawaiian ʻokina, not an apostrophe, and is pronounced as a glottal stop.”

Anyhow, the bit that offends you is not a quotation, it’s Scocca himself.

So if I understand you correctly, your disagreement with Scocca is that you think that lots of things may have happened while we weren’t looking (i.e. for the last several billion years), and some of them may have been a lot like this. It’s probably not a first occurrence, just a first observation. I agree!

But why would you think that Scocca disagrees? He was speaking loosely, as we often do, and saying “it’s a first occurrence” when he means, “it’s a first observed occurrence.” What’s the alternative? Scocca doesn’t know the sky was there before telescopes were?

Chethan. Yup, it works equally well for anything we can’t rule out. From ignorance follows (epistemic) possibility.

Now, that doesn’t mean we have to take every possibility equally seriously, or at all seriously. There, I’m in complete agreement with you. How seriously we take a possibility should always vary with how much evidence we have for it. I don’t take the possibility of gods any more seriously than the possibility of sub-Alpine elephants, because there’s no evidence for them.

But again — are we saying anything here with which Loeb would disagree?

@oldster: @OzarkHillbilly: Well, the fact that ‘Oumuamua is on an (unbounded) hyperbolic orbit certainly isn’t evidence that it’s alien. Every theory of star & galaxy formation predicts that there will be many, many small objects out there in-between stars; I remember reading that in fact, “rogue planets” should be more numerous than stars. There’s nothing extraordinary about observing the *first* extra-solar object.

A very depressing possibility. If we know most of what there is to know, then the world is not only much more boring, but also much less comprehensible than we might have hoped.

There are a lot of puzzles and anomalies out there, and my own hunch is that there are explanations for lots of them, explanations that we just don’t know yet. If we already know most of what there is to know, then there’s just a lot of random crap around for no reason. Could be! But disappointing.

@rikyrah: Good morning rikyrah and all!
I got nuthin on the post subject. Flying from Mexico City to Aguascalientes today. Since groups of Hispanics are constantly covered as the next threat to the US, if they track one moving toward Guanajuato, it’s me with second exchange son and his extended family. At last count about 12 of us are going 😊.
We mean you no harm, Republicans.

The quote in the OP pretty clearly has him arguing “it could be aliens! It could be aliens!” If he’d said instead “gosh, if it WERE aliens, we’d have been completely unprepared to observe that fact”, well, that would have been uncontroversial. So yeah, I think he’s getting way out in front of the evidence. Way out in front.

Fucking dissident IRA gobshites set a bomb off in Derry last nite. I’m so angry to wake up to this. It’s not about anything more than one gobshite talks other gobshites into thinking they should be in charge instead of SF. Fucking assholes, like there’s not going to be enough chaos after the UK leaves the EU without a transition agreement.

The thing about dark {matter,energy} is that they’re theorized to account for behaviour [at a much, much bigger scale] that does not comport with GenRel, right? And nobody knows what they are or how they work, but they -do- know that in order for the equations to work out, there’s gotta be something there. More precisely, there’s not *nothing* there.

Yes, we are unable to explain the function of some fundamental forces at work in the universe, that’s why I mentioned them.

And similarly, I’d say that if it turned out that ‘Oumuamua’s trajectory was unexplainable, we might not be able to say why, but “unexplainable” would rule out “natural objects”.

And similarly I would say there is something going on here that we are incapable of explaining. There are an infinity of things that we are unable to explain. The whole purpose of science is to explain the unexplainable. Most often the best we can say is that we can not explain a thing yet.

I freely admit to being a skeptic, and that short of an alien waving to us from his window, or us seeing a light sail or a booster engine falling to earth, or some other incontrovertible evidence I am unlikely to concede that a thing was an alien spacecraft.

@Chetan Murthy: A lack of evidence for something is not at all the same thing as overwhelming evidence of something’s antithesis.

At all.

The existence of aliens would not at all be surprising if it were to be eventually detected or proven and it wouldn’t violate any known natural law. It’s a super low probability thing given the lack of any other sign, but it isn’t that extraordinary an idea. We exist, and simply by existing we prove that life capable of going to the stars can exist. Positing that there’s more of it isn’t actually a stretch.

Occam’s Razor is really more what argues against assuming an extraterrestrial source.

But why would you think that Scocca disagrees? He was speaking loosely, as we often do, and saying “it’s a first occurrence” when he means, “it’s a first observed occurrence.”

Because it’s sloppy and wrong. His job is to inform, not misinform. Call me a pedant if you like, but he is a professional writer, not some blog commentor. His business is based on the proposition that words matter.

This is for Ozark…. On Point had Bill Anders, the guy who took the iconic “Earth Rise” picture from Apollo 8. A fellow called in and tried to get Anders to say that the picture was so awesome it must have been a religious moment for him. Anders talked about how men and math got them there and back and then, after saying he didn’t want to get into a religious debate, said:

One thing that impressed me, is that while Earth is physically insignificant, it is certainly important for humanity. It is also certainly very small… We are not the center of the universe, we are definitely out on the edge of nowhere out in space

@Immanentize: An old friend of mine once said to me, “For a grounded old troll, you are one spiritual motherfucker.” And it’s true, i have had many spiritual moments in my life, moments where I felt the connectedness of all that is around me and known my place in it. None of them were religious moments tho.

@JPL: It’s been wonderful. Mexico City is beautiful, there’s so much history and architecture to enjoy, the weather has been perfect. My exchange son loves history and architecture too, so he’s really enjoyed being able to show it to me. His wife isn’t as into that, so most of the time it’s been just me and Fernando and we feel as close as when he was with my family 24 years ago. I’m very happy.
Looking forward to being with his brother, and it will be sad to say goodbye to both of them and their fabulous country.

@OzarkHillbilly: A question that I am looking into and the issue that dark matter is used to address, has the possibility of up ending current theories of the Universe; not quantum mechanics – that is more solid than granite.

@Immanentize: Although it doesn’t snow often here, it does snow. I mentioned to a son that it was nice to have a couple of snow shovels. He mentioned that I didn’t have any shovels, and I reminded him that last year my neighbor and his son appeared and did my driveway.
It’s nice to live next to neighbors like that.

Last night, we had dinner with people who told us that Trump had made a reasonable offer on the wall etc. I am worried that most people will have heard him that way. They don’t know he’s offering to give back what he took away, and only temporarily at that.

@oldster: True but why I’m rooting against dark matter. If it is fictitious, than Newtonian (but not General Relativity (GR)) is wrong. That really opens up physics and might lead to the fusion of quantum mechanics and GR.

I’m a bit worried that things will continue to deteriorate this week and I’ll have a hard time getting home. With another stalemated “negotiation” , if I was working for no pay I would be calling in with Ebola about now. People have to earn money to live.

gregorg (@gregorg) Tweeted:
this feels like important context that isn’t coming through: Philips stepped in between the MAGAyouth and the African American youth they were surrounding. His drum and prayer was not a provocation, but a deflection and de-escalation. We should all be so brave.

The beauty of Mexico pales in comparison to the beauty of it’s people.

Very true. It has its problems, certainly; but the vast majority of Americans are so (deliberately) misled about what a modern and mostly safe country it is. If they could control the graft that impedes more progress and law enforcement, it could be a real rival to the US. Which is probably the point of the disinformation about about it.

The theory of alien communication as an explanation for this phenomena was briefly touched on and somebody gave a very good explanation for why we humans see aliens whenever we find something we can’t explain.

Like the Greeks and their mythology.

I know practically nothing about all this, and understand even less, but I don’t see how an object could escape another solar system. If there’s sufficient gravity to more or less hold things in place over there, how could this “rock” not only escape but maintain a sort of course elsewhere?

Certainly not the same as your level, but as an office assistant in B.U.’s General Biology Department, I assisted Sagan in setting up what was then a revolutionary interactive teaching device for freshman students back in the early 1970s. It was kind of goofy, but fun.

Every gravitational well has an escape velocity. If an object achieves that escape velocity, ir can escape it. Earth’s is about 25k miles/hr. Get something going that fast, and it’ll leave Earth’s gravitation. The solar system has an escape velocity, too. Typically, the way we accelerate things to fast enough, is a combination of rocketry, and “gravitational slingshots”. The latter is a little difficult to explain, and I’m not going to try, b/c been too long since I took physics. But it’s done all the time. If *we* can arrange for gravitational slingshots of our spacecraft, obviously some rock could end up getting slingshotted in the same manner. If it picked up enough speed, it might leave the solar system.

As of 21 July 2018, Voyager 1 is over 142.75 AU (21.36 billion km) from the Sun,[11] and is in interstellar space.[12] It gained the energy to escape the Sun’s gravity completely by performing slingshot maneuvers around Jupiter and Saturn.[13]

@OzarkHillbilly: It helps to be a little nuts to understand the subject. I’ve taken a few courses in the subject and it still puzzles me relative to the lack of clear meaning. It just isn’t open to physical interpretation and that makes it rather non-intuitive. The math, depending on the approach, becomes incomprehensible quickly. The heart of all quantum mechanics is the Heisenberg Uncertainty principle.

@Immanentize: I saw a contemporary interview where Anders says he was a devout Catholic but space travel undermined his faith because seeing hundreds of thousands of stars clearly in the darkness of space made him realize earth could not be unique.

@debbie: There are a # of ways. Gravity doesn’t just hold things in place, sometimes it kicks things around, like comets. It is possible that an object could get flung out of the solar system via a series of gravitational kicks (more likely it would stay here but it is possible) Chetan Murphy mentioned rogue planets above, there are also brown dwarfs that if they passed thru a solar system would screw everything up most likely kicking any number of things out (and in the core of our galaxy these things probably happen frequently). Another possibility is an exploding star tearing a planet apart and ejecting the pieces out into the cosmos.

Wait whut?
Gravitational force is always attractive, unlike the Coulomb force (electrostatic force) which can be both attractive and repulsive.
Comets that we see from the earth have extremely elliptical orbits around the sun.

@Cermet: I am a little nuts (ask anybody) but I’m not quite a psycho. Years back I would have liked to take a course on it but now…. I’ll just say that in the few years I have left on this planet I will choose to learn about something that isn’t quite so painful for me.

@debbie: Its the same principle as a car taking a turn at a sharp curve, if the car is too fast it can go flying off the road. You can understand this situation using either Newton’s laws or the conservation of energy. This is Physics 101.

@schrodingers_cat: Comets hang out in the Ooort Cloud, just floating around happy and content to be there in the icy cold until something passes close by and changes it’s orbit ever so slightly. This is an ongoing process and most things just kind of float randomly about bouncing around like billiard balls. Every now and again tho, one gets a kick that sends it towards the sun. Some comets return on a regular basis (Haley’s being the most famous) others have an orbital period that are so long they only come around once every few thousand years. Still others meet their ends by colliding with a planet (Shoemaker-Levy collided with Jupiter in 1994), or just fading away as the sun vaporizes them on their repeated journeys around it.

ETA And I see by you at 114 you already understand the mechanism so I am unsure of your question?

On November 17, 1986, the Japanese crew of a JAL Boeing 747 cargo freighter witnessed three unidentified objects after sunset, while flying over eastern Alaska. The objects seemed to prefer the cover of darkness to their left, and to avoid the brighter skies to their right. At least the first two of the objects were observed by all three crew members: Captain Kenju Terauchi (Japanese: 寺内謙寿), an ex-fighter pilot with more than 10,000 hours flight experience,

There’s a stack of reports from military and commercial pilots about seeing UFOs at distances of under 10K, Making maneuvers that normal aircraft can’t do. The common debunking explanation is that stars are too far apart to permit interstellar travel at sub C speeds. That supposes that the occupants are human like. Looking at the gains science is making, it obvious to me that a century from now there will be genetic manipulations, AI, and machine implants we can’t imagine. If my lifespan is 1000yr+, what’s a 6 yr trip to Centauri? I’ve spent more than that just commuting to NYC. Unfortunately it’s likely that the technical harnessing of the energies needed to make that kind of trip would be the tool of our demise.

Any spacefaring civilization would have succeeded in avoiding the ecological disasters we are creating. That could done by adhering to a philosophy or genetic manipulation that limits psychological variations. Their motives and thought processes would be, well, quite alien to humans

@OzarkHillbilly: I too don’t have too many years available but I intend to try and crack that nut and whether I do (LOL, not too likely) or not, I refuse to lose the mind first; besides, I hated advanced math in the past that now I get a kick out of relearning some of it as well as learning a few new areas. What really shocked me in my new study of the subjects is that 1) the kids today have it so easy with google 2) youtube courses in all subjects, even graduate level GR have massive levels of info spoon fed 3) far better and more choices in text books that are writen by people who decided that not everyone has an IQ above 101.. I’ve also discovered that the methods that had been used to teach me were terrible, sometimes misleading and almost all the times so boring that no one had a right to be awake in most the classes. Damn, born at the wrong time (to learn math); right time to avoid the worse of AGW, Mixed bag – not really.

The first thing I thought of when I read this was Arthur C. Clarke’s Rendezvous with Rama. Of course, in Clarke’s timeline, we already had interplanetary spacecraft with the chops to go investigate. In this timeline we have…Republicans

@schrodingers_cat: No, it’s not, but gravity can be strong enough to pull an object towards it without being strong enough to capture it, thereby changing another objects trajectory or even having a slingshot effect.

@debbie: Classical mechanics can be a lot of fun!
ETA: That’s why I gave the RL example of the car taking a turn on the sharp curve, that’s why many sharp turns are banked to increase that velocity at which the car will go off road.

LOL, I just don’t have that kind of brain. I never have. I read Astrophysics for People in a Hurry, understood it while reading it, but retained the information for only a short time. Poof, gone. At least my awe of the universe remains as strong as ever.

ETA: I do understand your RL example; my head can’t wrap around this happening at such vast distances and speeds.

@schrodingers_cat: I like that ‘can be’. In fact, the physics of gravitational capture is a mess. An incoming artifact may simply be ‘captured’ into an orbit that has a lifetime greater than the age of the universe. That would make it consistent with a little ‘unmentionable’ detail that comes out of scattering theory– that capture doesn’t work in quantum mechanics. Oh, well.

I was born at the wrong time and went to the wrong school to learn much of anything, at the peak of the baby boom. By the time I entered HS the only thing they were trying to do was get us out the door (I had over 600 in my class). I was bored all the time. By the end of HS I had had enough to last a while. By the time I felt motivated enough to go back, anything more than dabbling was not an option.

@Procopius: 1839 or 1889, maybe. But in 1939 the ramjet was known, and the behavior of semiconductors was sort of known – the ‘cat whisker’ naturally-occurring rectifier was well-known but the science of the day wasn’t 100% sure how it worked. Clarke’s Law still feels correct, though.

This article, from the Scientific American blog, might be more to people’s tastes. It does make the claim that ‘Oumuamua is weird in surprising ways. It has claims that ping my skeptic meter, like:

In a paper published a decade ago, we predicted an abundance of interstellar asteroids that is smaller by many (two to eight) orders of magnitude than needed to explain the discovery of ‘Oumuamua, assuming it’s a member of a random population of objects. Put another way, ‘Oumuamua implies that the population of interstellar objects is far greater than expected. Each star in the Milky Way needs to eject 1015 such objects during its lifetime to account for a population as large as ‘Oumuamua implies.

My sound built into my new System 76 laptop quit very recently. The machine is about a month old now. When I opened the system control panel, it shows the output device for the sound to be “Dummy output”.

When I plug in USB speakers, (Logitech stereo, sounds very good) I get three choices, all into the Logitech speakers, Analog, Analog with bass Boost, and Digital. They all sound good. When I remove the USB plug, back to Dummy Output.

The retired earth/space science and astronomy teacher in me needs to come out to play. Generally, the tone of this discussion is pretty science forward but there are a couple of facts or concepts I would like to tighten up.

The speed needed to leave Earth’s surface and enter Earth orbit is about 9 km/sec. This includes overcoming air resistance. In Earth orbit, you are still subject to a considerable pull by Earth’s force of gravity which is why the term “zero gravity” irks me no end. To completely leave Earth’s gravitational influence to travel to the Moon or Mars, that escape velocity becomes about 11 km/sec. However, you are still held in thrall by the Sun’s gravity. To completely leave the solar system and the Sun’s gravity, from the distance of the Earth, you need about 42 km/sec of velocity. The five man-made objects currently on trajectories to leave the the solar system are traveling between 14 and 17 km/sec but they achieved these velocities in gravitational assist fly-bys of planets much further from the Sun than the Earth. Out there, the Sun’s gravitational pull is much less so they needed only get to solar system escape velocities from the point where they last picked up a gravitational assist.

Traveling from one object to another in the solar system is not a matter of heading off in a straight line toward your destination. Rather, you need to put yourself in an orbit around the Sun that intersects the orbit of your target. Similarly, when an object, whether it is one of our artificial probes or ‘Oumuamua leaves the solar system, it puts itself in an orbit around the center of the Milky Way galaxy. To completely leave the Milky Way from the distance of the Sun, escape velocity is about 537 km/sec.

I meant to touch on some other things but I find myself becoming ponderous. If this comment doesn’t kill this thread, I don’t know what will.

@schrodingers_cat: I take no offense. While I am a rather prolific reader of physics, astronomy, cosmology, etc etc etc, as I said to Satby above, the depth of my knowledge on these subjects is surpassed only by the depth of my ignorance. In other words, I know enough to have a vague idea of just how much I don’t know. Being corrected on these subjects bothers me not at all.

And me three. Astronomy and quantum mechanics (hence the nym). I find myself trying to cut what I post down to about 10% of what I am thinking. Hey I’m retired now. I can be the wise-ass old man. Back in my day we calculated integrals by hand with pencil and paper and we liked it. Get out of my Hilbert space!

@OzarkHillbilly: HEE HEE, I wish I’d had more students like you. If I felt 2-3 kids in a class were really interested in the subject matter, I was good. I found that being a public school teacher, I needed to be happy with very small victories. Also, I was sometimes surprised by which students I was reaching.

Back in my day we calculated integrals by hand with pencil and paper and we liked it.

Heh, reminds me of the scene from Apollo 13 where everyone in ground control is double checking Lovell’s math with slide rules. I actually owned a rotary slide rule at one point. Probably not that rare but it was the only one I’d ever seen and it was a somewhat prized possession. Not that I ever had any need for it, just thought it was kinda cool.

I was a horrible student. Bored to tears, skipping every class except for tests, never studying anything and still managing to pull down Bs and Cs. Except for one class: Mrs Luco’s (Loco Luco was her nickname) she was a no nonsense take no bull Mathematics teacher that everybody hated. I had her for Trig and Anlyt one year, Calc the next, and I never missed a class. Somehow someway she made me want to be there, want to actually learn, not just pass the tests.

Heh, reminds me of the scene from Apollo 13 where everyone in ground control is double checking Lovell’s math with slide rules

I’ve programmed computers for over 40 years and even though it’s been almost that long since I’ve used a slide rule I’ve found that learning to use a slide rule was excellent training for writing correct programs. You always had to worry if you transformed to the final answer correctly so you learned to always find was to double check. A lot of computer programs will spit out a number and I’ve run into programmers that seem to think if the program doesn’t dump core and spit out a number, your job was done.

@schrodingers_cat: I was lacking too much of the tensor stuff. I was trying to do that stuff on my own by finding various people’s course notes, but didn’t have time in the week to do both.

So I backed out of the GR course for now. Im taking a SR course on Coursera but unfortunately it’s mostly aimed at the no math crowd.

Bought myself a Kindle edition of Misner, Thorne and Wheeler and hoping that can give me (all 1600 pages of it!) the math exercise I’m looking for the tensor calculus. Also eyeing a couple tensor books Amazon is suggesting.

In a different but easily findable piece (https://blogs.scientificamerican.com/observations/6-strange-facts-about-the-interstellar-visitor-oumuamua/) Loeb shares more than two data points regarding ‘Oumuamua’s weirdness. He presents them as “6 strange facts,” but in truth the six are categories that intriguing data points have been sorted into. Looking over the set, the picture is fascinatingly more complicated and interesting than your summarization presents, and not so easily handwaved away. For just one example, the most interesting thing about the trajectory is not that it was hyperbolic, but that the trajectory varied a 10th of a percent from what it should have been based on the sun’s gravity alone. This variation is not a small number. And the natural explanation for it (cometary outgassing) doesn’t fit the observed data. First, to achieve that much variation would require the conversion of at least a tenth of the object’s observed mass, but (a) we don’t see that much change, (b) there was no tail, and (c) there was no alteration in ‘Oumuamua’s rotation period. Nobody has yet explained A; B can only be explained if the release was made of pure water and nothing else, which doesn’t match with other observations or what we know about space rocks in general; and C has literally never been seen before in connection with outgassing, period.

While there might indeed be perfectly natural explanations for this and other observed ‘Oumuamua oddities, which are numerous, we do not yet know what they are. We really don’t. Which is cool. Science advances most rapidly when confronted with verifiable data that stands outside our current understanding, forcing us to uncover facts and figure out connections we were previously oblivious to.

In his SciAM blog piece, Loeb shares an interesting idea. Assuming we can develop faster technologies within the next two decades, there would still be time to send a probe to check out ‘Oumuamua directly. I would love to see that.

Does this mean that the kids in the video are beyond redemption? In the abstract, of course not. In this particular case, I don’t know. More crucially, I don’t care, because the more salient fact is that they almost certainly won’t try. Why would they? Not only are their school and families hotbeds of the kind of racism they expressed towards Nathan Phillips, but the media has immediately rallied to offer them a way out in the form of pleading youthful ignorance. They’re being offered field trips where the people they hurled abuse at are expected to teach them what their parents and teachers failed to—or rather, didn’t even try to. What, exactly, is the motivation here for change?

My connection with Carl was unusual. We met because of something about him not many people know, which is that he was a closet circus buff. By coincidence, I was a magazine journalist who also happened to be a graduate of the Ringling Brothers Clown College. When he learned about that he agreed to give me an interview if I would come up to Ithaca and do a full costume/makeup clown performance for his son Nicholas and the neighborhood kids. The show took place in his driveway. After it I cleaned up, we did the interview in and around dinner, and became friends. (A few days after Viking landed on Mars I snuck him away from JPL for a break because he wanted to go see the Ringling Red Show, which was in LA at the time, and he was so tired he fell asleep in the middle of it…) He was a good man, a great scientist and communicator, and I miss him.

@Aleta: “The Black Robe” remains one of my very favorite movies ever, up there for me with “Pan’s Labyrinth”, “Synecdoche, New York”, “Magnolia” and a few others that have so deeply affected me. I was just thinking how “The Black Robe” had to be around 20 years old, since it seemed that long ago I’d seen it (only watched it the one time when it was first released to theaters). It’s actually nearly 30 years old. Damn.